A display device displays an image using an element that emits light. Flat panel display devices have been widely used as display devices, where representative flat panel display devices include liquid crystal displays and organic light emitting display devices.
In the liquid crystal display, because the liquid crystal is not a self-emitting element, an additional light-emitting component, such as a backlight, is required. Light emitted from the backlight then passes through a color filter to express a color. Contrarily, because the organic light emitting display device uses a self-emitting organic light emitting diode, the organic light emitting display device does not use a backlight, has a simple structure, and has high light extraction efficiency. For this reason, the organic light emitting display device is in the spotlight.
In the display device, to express a desired color in one pixel, at least three subpixels, including red, green, and blue are used. That is, to express a desired color in one pixel, an amount of light emitted from each subpixel out of a red subpixel, a green subpixel, and a blue subpixel is controlled. In this case, a transistor is used to control the amount of light emitted from each of the red subpixel, the green subpixel, and the blue subpixel. As such, to express a desired color in one pixel, the display device requires at least three subpixels, and requires a transistor for each of the three subpixels. Therefore, at least three transistors are required in one pixel.